Strategic surprise is a precious weapon in terrorist campaigns. Al Qaida managed to achieve this spectacularly on 9/11. Since then, counterterrorism efforts have been improved considerably, both within the American homeland and abroad. The result of this much-heightened state of alert: Out of dozens of significant jihadi terrorist plots against the Western Alliance, only a very few have not been interdicted. 

Whether it is procuring or improvising weaponry, undertaking surveillance or testing an attack plan, specialist training and expertise within a terrorist team are needed for a plot to have a reasonable degree of success. Furthermore, the execution of a commando-style plot, such as hijacking or sabotage, would require a sizable group of assailants. But any major plot has a good chance of being stopped—the more ambitious the plot, the more guys who are involved, the greater is this chance. Too many terrorists spoil the plot.

Indeed, since 9/11, the only successful plots against the Western Alliance have involved improvised explosive devices and small arms. The development of technically sophisticated plots using innovative weapons, such as those of mass destruction, is optimally fostered within safe havens, which have been militarily denied to Al Qaida since 9/11.